1. Field of the Invention
The present invention is broadly concerned with an improved counterflow water cooling tower construction characterized by an eased inlet structure serving to minimize undesirable air turbulence at the air inlets of the tower, thereby increasing the overall cooling efficiency thereof. More particularly, it is concerned with such a counterflow tower wherein the fill structure (preferably cross-corrugated film-type) presents a lower side marginal air entrance surface which extends below and inwardly at an oblique angle from the edge of the upper inlet-defining wall surface of the tower casing, with the bottom of the fill structure being generally horizontal. In this way, the velocity of entering air is maximized, and even air flow is facilitated within the substantially unrestricted air flow zone between the underside of the fill and the lowermost cold water collection basin of the tower.
2. Description of the Prior Art
Counterflow water cooling towers broadly comprise an upright casing supporting an elevated water distribution system, an underlying water-dispersing fill, means such as powered fan(s) for drawing ambient-derived cooling air currents into the casing through appropriate inlets and upwardly through the tower casing and fill, and an underlying cold water collection basin. The distribution system serves to receive initially hot water and to distribute the same for gravitation through the underlying fill structure. The latter can be of the splash or film variety, but in all cases serves to effect a thermal interchange relationship between the initially hot water descending through the fill and the countercurrently upwardly flowing air currents.
A persistent problem with counterflow towers stems from the tendency of such towers to suffer from substantial air flow disruption and turbulence at the region of the lower air inlets thereof. This in turn creates uneven and/or deprived air flow through the fill structure, particularly at the outboard regions thereof immediately adjacent the tower casing. Such an air flow pattern detracts from the cooling efficiency of the tower, which is maximized where the air flow is substantially uniform.
A variety of counterflow air inlet designs have been proposed in the past, but all suffer from poor inlet flow distribution to a greater or lesser degree. For example, it is known to provide fill structure within the tower which extends to a point essentially flush with the upper defining edges of opposed air inlets, and is also known to provide outwardly extending fins or air entrance guides above the inlets. U.S. Pat. No. 4,873,028 describes an inlet/fill arrangement wherein the fill structure includes a plurality of side-by-side trapezoidal-shaped fill sheets which cooperatively present an oblique, non-horizontal air entrance face. The fill structure in this instance extends essentially the full height of the tower down to the collection basin. Similarly, U.S. Pat. No. 3,983,190 provides full-height fill structure presenting an oblique air entrance face, but here again the fill extends down to the collection basin and effectively blocks lateral air flow through the tower.
There is therefore a decided need in the art for an improved counterflow tower design which ameliorates the problems associated with air flow disruption at the inlets thereof and thereby enhances overall cooling efficiency.